D&D 5E Do the Monster Building Guidelines Work?

[dave2008]

This thread was spawned by a conversation I was having with @Neonchameleon about the monster building guidelines in the Dungeon Master's Guide (DMG). I like the monster building guidelines in the DMG. However, the frustrate some people and others think they are broken or simply don't work. They point to discrepancies between the CR in the Monster Manual (MM) and the DMG as "proof" that they are broken. Is that true? If it is true, is that proof of an error in the guidelines or an error in the execution?

First, I believe for the most part the guidelines work. They can't cover all cases and provide all the features that affect CR, but they do, IMO, a good job. We do have to accept in somethings you have to make a judgement based on little to no guidance. They are however a bit obtuse, so I understand they create a lot of confusion. I think that is why many say they don't work, they don't understand all the in and outs of the guidelines. So I maintain that there are not as many discrepancies between the DMG and the MM as people think.

Second, I believe many discrepancies between the DMG and the MM are caused by errors in the MM and not the DMG.

Are Monsters better now?!
I will review the 2nd point first. Basically, over the course of 5e WotC has tweaked their monsters. What is interesting is that as they have done so, they have consistently become more in line with the DMG, not less so. This leads me to believe the DMG is fairly good at what it is supposed to do and early differences were an error in execution of the guidelines.

I quick check of this is to look at dragons. In the MM, the ancient green dragon has a CR of 22. Similarly, in Fizban's Treasury of Dragons (FToD) the ancient sapphire dragon has a CR of 22. The green dragon has a higher AC, more HP, and does significantly more damage than the sapphire dragon. So how can they have the same CR? Well, the MM dragon's CR is wrong.

When I check the CR of the green dragon with DMG rules, I get a CR of 24 not 22! However, when I check the sapphire dragon with DMG rules I get a CR of 22, the same as listed in FToD. The design of the monster has shifted to match the DMG rules more closely as WotC has gotten better at using their own guidelines.

Spoiler: Dragon Reference Statblocks

The Proof is in the Black Pudding
Now back to the first question: how accurate are the CRs in the MM? I have heard many tails about how awful the CRs are in the MM when compared to the DMG. However, I generally find the pretty accurate. But I have not done an exhaustive check. I would like to do so now. However, I don't really have the time so this will be a slow process. I will tackle this task in order as I make my way through the MM. To start here are my findings, with comments, for the As:

Spoiler: Monster CR check: "A"

Monster Name	MM CR	DMG CR	Delta	Notes
Aarakocra	0.25	0.25	0	DMG CR was .1875, so could be 1/8 or 1/4 depending how you want to round.
Aboleth	10	10	0
Angel: Deva	10	9	1	Off. low (CR 8)
Angel: Planetar	16	15	1	Off. and Def. low (CR 15); effective use of blade barrier could increase CR
Angel: Solar	21	21	0	Assumes damage immunities & 2 targets for searing burst (I think that is a stretch)
Animated Armor	1	1	0
Flying Sword	0.25	0.5	-0.25	DMG CR was .375, so could be 1/4 or 1/2 depending how you want to round.
Rug of Smothering	2	2	0	assumes "damage transfer" trait adds +1 to CR
Ankheg	2	2	0
Azer	2	2	0	DMG CR as 1.5, so couldl be 1 or 2 depending on how you want to round

I will add more monsters as I get them done. But this will be all for a while. I am much to busy to be doing this right now!

PS - I know the DMG guidelines do not match WotC internal spreadsheet 100%, that does not mean they are broken.

 

[overgeeked]

First, CR in regards to actually challenging PCs in combat is utterly broken. Which is wild considering that's literally the point of the CR system.

Second, whether CR is consistent between the MM and DMG seems essentially irrelevant considering the first point above. Checking the latest monsters would probably be a better use of time.

I've found that Blog of Holding has done a far, far better job getting the numbers to work that WotC has.

5e monster manual on a business card

Lately I’ve been doing statistical analysis on D&D 5e monsters to see how they’re built, and I’ve learned some interesting things: the DMG monster-creation guidelines don&#821…

www.blogofholding.com

 

[dave2008]

First, CR in regards to actually challenging PCs in combat is utterly broken. Which is wild considering that's literally the point of the CR system.

No, you are talking about the encounter building system which is related but different. CR works fine.

Second, whether CR is consistent between the MM and DMG seems essentially irrelevant considering the first point above. Checking the latest monsters would probably be a better use of time.

It is relevant because people make a claim that may or may not be true. I would like to find out. I know my experience is different from what a lot of people have had with MM in relation to the DMG. It is interesting to me, so it has relevance to me.

I've found that Blog of Holding has done a far, far better job getting the numbers to work that WotC has.

5e monster manual on a business card

Lately I’ve been doing statistical analysis on D&D 5e monsters to see how they’re built, and I’ve learned some interesting things: the DMG monster-creation guidelines don&#821…

www.blogofholding.com

I disagree. Paul's understanding of the guidelines is flawed and his analysis is based mostly (if not completely) on the MM which is, to a greater extent then newer books, a flawed execution of the DMG guidelines. And if my analysis proves the MM is a poor implementation of the CR guidelines then that completely throws off his analysis.

I have discussed this with Paul before and my take away was he doesn't understand the guidelines.

One caveat, it has been years since I reviewed the blog of holding so he may have updated things since I last looked.

 

[overgeeked]

No, you are talking about the encounter building system which is related but different. CR works fine.

So what's CR for if not as a means to rate monsters compared to PCs?

I disagree. Paul's understanding of the guidelines is flawed and his analysis is based mostly (if not completely) on the MM which is, to a greater extent then newer books, a flawed execution of the DMG guidelines. And if my analysis proves the MM is a poor implementation of the CR guidelines then that completely throws off his analysis.

I have discussed this with Paul before and my take away was he doesn't understand the guidelines.

One caveat, it has been years since I reviewed the blog of holding so he may have updated things since I last looked.

He's regularly analyzed the new monsters as new monster books come out and updated his numbers. He's also written or co-written several monster books for 5E and monster design systems for 5E.

 

[FallenRX]

This thread was spawned by a conversation I was having with @Neonchameleon about the monster building guidelines in the Dungeon Master's Guide (DMG). I like the monster building guidelines in the DMG. However, the frustrate some people and others think they are broken or simply don't work. They point to discrepancies between the CR in the Monster Manual (MM) and the DMG as "proof" that they are broken. Is that true? If it is true, is that proof of an error in the guidelines or an error in the execution?

First, I believe for the most part the guidelines work. They can't cover all cases and provide all the features that affect CR, but they do, IMO, a good job. We do have to accept in somethings you have to make a judgement based on little to no guidance. They are however a bit obtuse, so I understand they create a lot of confusion. I think that is why many say they don't work, they don't understand all the in and outs of the guidelines. So I maintain that there are not as many discrepancies between the DMG and the MM as people think.

Second, I believe many discrepancies between the DMG and the MM are caused by errors in the MM and not the DMG.

Are Monsters better now?!
I will review the 2nd point first. Basically, over the course of 5e WotC has tweaked their monsters. What is interesting is that as they have done so, they have consistently become more in line with the DMG, not less so. This leads me to believe the DMG is fairly good at what it is supposed to do and early differences were an error in execution of the guidelines.

I quick check of this is to look at dragons. In the MM, the ancient green dragon has a CR of 22. Similarly, in Fizban's Treasury of Dragons (FToD) the ancient sapphire dragon has a CR of 22. The green dragon has a higher AC, more HP, and does significantly more damage than the sapphire dragon. So how can they have the same CR? Well, the MM dragon's CR is wrong.

When I check the CR of the green dragon with DMG rules, I get a CR of 24 not 22! However, when I check the sapphire dragon with DMG rules I get a CR of 22, the same as listed in FToD. The design of the monster has shifted to match the DMG rules more closely as WotC has gotten better at using their own guidelines.

Spoiler: Dragon Reference Statblocks

View attachment 302137
View attachment 302138

The Proof is in the Black Pudding
Now back to the first question: how accurate are the CRs in the MM? I have heard many tails about how awful the CRs are in the MM when compared to the DMG. However, I generally find the pretty accurate. But I have not done an exhaustive check. I would like to do so now. However, I don't really have the time so this will be a slow process. I will tackle this task in order as I make my way through the MM. To start here are my findings, with comments, for the As:

Spoiler: Monster CR check: "A"

Monster Name	MM CR	DMG CR	Delta	Notes
Aarakocra	0.25	0.25	0	DMG CR was .1875, so could be 1/8 or 1/4 depending how you want to round.
Aboleth	10	10	0
Angel: Deva	10	9	1	Off. low (CR 8)
Angel: Planetar	16	15	1	Off. and Def. low (CR 15); effective use of blade barrier could increase CR
Angel: Solar	21	21	0	Assumes damage immunities & 2 targets for searing burst (I think that is a stretch)
Animated Armor	1	1	0
Flying Sword	0.25	0.5	-0.25	DMG CR was .375, so could be 1/4 or 1/2 depending how you want to round.
Rug of Smothering	2	2	0	assumes "damage transfer" trait adds +1 to CR
Ankheg	2	2	0
Azer	2	2	0	DMG CR as 1.5, so couldl be 1 or 2 depending on how you want to round

I will add more monsters as I get them done. But this will be all for a while. I am much to busy to be doing this right now!

PS - I know the DMG guidelines do not match WotC internal spreadsheet 100%, that does not mean they are broken.

I got cr22 from from the green dragon.

Ive found most MM statblocks to be on point the main thing is the virtual damage stuff you have to account for with conditions, tey value conditions equal to the lowest level spell level they appear in. Doing that fixed quite a bit.

 

[FallenRX]

So what's CR for if not as a means to rate monsters compared to PCs?

He's regularly analyzed the new monsters as new monster books come out and updated his numbers. He's also written or co-written several monster books for 5E and monster design systems for 5E.

He is right, the issue is the DMG encounter building rules are just broken, using the CR system with Xanathars guide actually works infinitely better its not funny, Xanathars guide is a replacement for it, its why they are using that as the basis for 2024.

 

[overgeeked]

He is right

No, he’s not. Challenge Rating has a definition and it’s hard coded into encounter design. They are not separate as he claims. From the monster building section, “A single monster with a challenge rating equal to the adventurers’ level is, by itself, a fair challenge for a group of four characters.” That’s what CR means.

That Xanathar’s breaks that correlation and is a better encounter design system shows CR is broken.

 

[CrashFiend82]

I also calculated a CR 24 for the Ancient Green Dragon (without Lair Actions) so I am curious where your lower 22 comes from.

Hp 475 (90) from Legendary Resistance - 22
AC 21 +1
Defensive CR - 23

DPR - 132 (20)
Attack Bonus +15 - (30) +5
Offensive CR - 25
Average CR - 24
In an early video Crawford (I think) stated it was intentional that dragons were stated above there "calculated" CR intentionally since dragons were intended as the iconic D&D monster.

 

[dave2008]

I got cr22 from from the green dragon.

Here is how I calculated, where do you think I made a mistake?

Defensive CR:
HP: 385 + 90 (legendary resistance) = 475 effective = CR 22
AC: 21 + 2 (3+ saving throws, step 15) = 23 effective = +2 to CR
Defensive CR = 22 + 2 = 24

Attack CR:
DPR:

R1 = 154 (Poison Breath, 2 targets per "Overall Damage Output") + 51 (3 tails) = 205​

R2 = 44 (2 claws) + 29 (bite) + 51 (3 tails) = 124​

R3 = 44 (2 claws) + 29 (bite) + 51 (3 tails) = 124​

DPR = 205+124+124/3 = 151 = CR 21
Attack Bonus/DC: +15/ 22 = +2 to CR
Attack CR = 21 + 2 = 23

CR = 24+23/2 = 23.5 rounded up to 24

Ive found most MM statblocks to be on point the main thing is the virtual damage stuff you have to account for with conditions, tey value conditions equal to the lowest level spell level they appear in. Doing that fixed quite a bit.

Yep

 

[dave2008]

No, he’s not. Challenge Rating has a definition and it’s hard coded into encounter design. They are not separate as he claims. From the monster building section, “A single monster with a challenge rating equal to the adventurers’ level is, by itself, a fair challenge for a group of four characters.” That’s what CR means.

The encounter guidelines are based on XP. The XP budgets are modified by difficulty. That difficulty is based on XP per day and encounters per day. This calculation is also affected by the number of monsters and the number of PCs. Those are the hard numbers with interactions between them.

The simple CR of a monster is not intended to tell you much. It is intended to be plugged into the encounter builder.

You quoted a "fair challenge" which is a vague measure and is a term (fair) never used in the encounter builder. I am fairly confident in my viewpoint on this.

That Xanathar’s breaks that correlation and is a better encounter design system shows CR is broken.

I guess I need to understand what you mean by "broken." How is CR broken? What is it not doing that you feel it should?